There has been a special class created for the current land speed record held by flathead engine powered vehicle . The most refined flathead to date can develop 700 hp (525 kW) and has a documented top speed of 300 mph (483km/h), although this may be broken in the near future.
Ford Motors produced three complete flathead V8 engine family lines, all with valves located beside bore holes, between 1932 and 1953. There are a variety of displacement engines within each of the three families, but with each family, the piston retains the same bore placement in the block. The flathead, “L” head, flatty, or medium block is initially, in 1932, a 221 cu in (3.62 L) engine. This first version has the exhaust/intake valves in the block, a water pump at each cylinder, with twenty-one bolts sealing the heads. This is followed by another family branch that begins with the 136 cu in (2.23 L) in 1937 which offers 60 hp (44.74 kW) and aptly named the “V8-60”. This new engine has water pumped from the front of the block and only 17 bolts fastening the heads down. In 1938 the company markets a more substantial version of the 221 medium block that has been bored to 239 cu in (3.9 L) with 24 bolts now needed to secure the heads. A big change for the flathead in 1948 is the distributor is now mounted vertically and into a direct line with the cam shaft. A new flathead 337” big truck” engine is added to the line-up in ’48 through 1949 is the only V8 Ford to have the distributor mounted to the rear of the block. The 337 replaces the V12 under the hood of the Lincoln Zephyr beginning in 1949. The flathead remained in production for a full 21 years in the USA and was the choice engine for hot rod enthusiasts and commonly seen on race tracks of the day. A twenty-first century publication of Ward’s Magazine rates this V8, designed and developed by Ford Motors, as one of the ten most significate automobile engine developments of the twentieth century.
The flathead is revolutionary without doubt, but it is not without a number of faults, although many of these have been solved by aftermarket equipment, back-yard mechanics or hot rod enthusiasts. The cooling system must be maintained regularly to prevent overheating and possibly cracking the block. The exhaust is funneled downwards, past the pistons, through the water cooling channels before exiting the block. The passages gasses must move down are narrow, an irregular sized and have a poorly finished inner surface which adds to the heat build-up in the block. The simple water pump is not efficient enough for the V8 and will not be improved on to any degree for Ford until 1948. The iron block is formed in a rough sand casting and if the inner surface of passages are polished the efficiency of the exiting gas is improved. Openings can often be bored 1/8” and then polished, but this depends on the thickness of the iron in the block and an “overbore” could be up to 3/16” over the factory size. The boring process could raise the power output by as much as 13%, but if a sand pit is uncovered then the block will fail and must be discarded.
The crankshaft that Ford makes is quickly produced from a casting rather than a very expensive and time consuming machining process. Heat treatment processes and handling methods that the Ford Company pioneered and patented are used to make the cast crankshaft just as strong as the turned variety, but at a far lower cost. An eight cylinder engine in a “V” configuration has a shorter crankshaft than the more primitive in-line blocks and commonly uses two connecting rods on one throw-one piston from each opposing bank. The Flatty became a favorite of the hot rod set and all kinds of aftermarket performance equipment became readily available to fill a growing demand. The best crankshaft for a nostalgic Hot Rod enthusiast would need these days to power a retro or a “Correct Hot Rod” is a four inch (101.6 mm) stroke unit from the Mercury Division, This choice part can be identified by the cleaning plug at the front of the shaft and is the crank that Ford used on all its engines from 1949 until ‘53. The hot rod crowd would “bore and stroke” the engine-enlarge the hole for the piston and use longer connecting rods to increase the cubic inch displacement. The main bearings on the flathead until 1935 were poured and required a fully equipped shop with a skillful technician to replace them. From 1936 production onward the poured bearing is replaced by a shell style, which are also available to fit the original 221 engine. The bearing is easy to install and a low cost adding tom the appeal of the flathead to the back yard mechanics. The engine has highly pressurized oil for lubrication-the same as a modern engine, and, although it adds no power, it gets rid of a complicated jet lubrication system that is often located in the oil pan. A prospective buyer of a used flathead can tell the condition of the main bearings and the connecting rods by observing the analog oil temperature gauge with the engine warm and the crankcase filled with the normal viscosity oil.